In the conventional practice of color photography, silver halide film is developed by a chemical technique, requiring several steps consisting of latent image development, bleaching, and fixing. While this technique has been developed over many years and results in exceptional images, the technique requires several liquid chemical solutions and precise control of times and temperatures of development. Further, the conventional silver halide chemical development technique is not particularly suitable for utilization with compact developing apparatus. The chemical technique also is not easily performed in the home or small office and is certainly not suitable for use in a hand-held camera.
Imaging systems that do not rely on conventional wet processing have received increased attention in recent years. In one approach, known as instant photography and popularized by Land and co-workers, a specially prepared sheet film is exposed and processed in a camera by the mechanical application of a viscous high pH fluid containing a developing agent and other addenda. Only a single image is produced and the ability to provide a compact camera is limited by the size of the desired image. Further, the dye images produced are limited in stability and capacity for magnification by the inherent characteristics of the system.
In a distinct art, photothermographic imaging systems have been employed for producing silver images. Typically, these imaging systems have exhibited very low levels of radiation-sensitivity and have been utilized primarily where only low imaging speeds are required. The most common use of photothermographic elements is for copying documents and radiographic images. A method and apparatus for developing a heat developing film is disclosed in U.S. Pat. No. 5,587,767--Islam et al. Summaries of photothermographic imaging systems are published in Research Disclosure, Vol. 170, June 1978, Item 17029, and Vol. 299, March 1989, Item 29963. Thermally developed films have not been generally utilized in color photography. However, heat development color photographic materials have been disclosed, for example, in U.S. Pat. No. 4,021,240--Cerquone et al. and U.S. Pat. No. 5,698,365--Taguchi et al. Commercial products such as Color Dry Silver supplied from Minnesota Mining and Manufacturing Co. and PICTROGRAPHY.RTM. and PICTROSTAT.RTM. supplied by Fuji Photo Film Co., Ltd. have been put on the market. Furthermore, U.K. Publication 2,318,645 discloses an imaging element capable of providing a retained viewable image when imagewise exposed and heated.
A recent innovation in color negative film has made use of a thrust cartridge containing color negative film. Such cartridges are disclosed in U.S. Pat. No. 4,834,306--Robertson et al and U.S. Pat. No. 5,003,334--Pagano et al. The film contained in such a thrust cartridge can contain a magnetic layer that allows recording of information during manufacture, exposure, and development of the film. Such film is disclosed in U.S. Pat. No. 5,215,874--Sakakibara. The film and cartridge can contain additional provisions for data storage such as DX bar code data and frame number bar code data. Such elements are disclosed in U.S. Pat. No. 5,032,854--Smart et al, U.S. Pat. No. 5,229,585--Lemberger et al, and U.S. Pat. No. 4,965,628--Olliver et al. The thrust cartridge can also be made light-tight so that unexposed or imagewise exposed film that has been rewound into the cartridge can be stored without further exposure of the film within the cartridge. These thrust cartridge films have the advantage that they can be more easily manipulated for copying, digital reading, and storage.
Camera and image capture apparatus technology has been developed over many years and a substantial literature exists. Numerous disclosures relate to exposure optimization by controlling the aperture and the shutter speed of the imaging system. Examples of disclosures relating to exposure control include U.S. Pat. No. 5,382,997--Sato et al and U.S. Pat. No. 4,792,820--Norita et al. Many disclosures exist relating to electronic flash. For example; U.S. Pat. No. 5,720,038--Fukuhara et al and U.S. Pat. No. 4,285,588--Mir disclose means to reduce red-eye effects, U.S. Pat. No. 4,331,400--Brownstein et al discloses a means to improve exposure by selecting between fill-in and full flash modes, and many disclosures relate to metering means to determine ambient light conditions and subsequent control of the flash as in U.S. Pat. No. 4,727,389--Raschke. Other photographic camera disclosures relate to format selection. For example, U.S. Pat. No. 5,583,591--Saito et al describes a system in which the format of the picture (i.e. panoramic, HDTV, or normal) can be selected at the time of the exposure. Film position control necessary for accurate frame exposure is addressed in disclosures such as U.S. Pat. No. 4,479,705--Tamamura et al and U.S. Pat. No. 5,583,591--Saito et al. Numerous systems have been described to perform auto-focus functions in photographic cameras. Examples include U.S. Pat. No. 5,406,348--Wheeler, U.S. Pat. No. 4,710,013--Wong, and U.S. Pat. No. 4,860,045--Hamada et al. Present camera systems typically yield excellent results. However, due to the lack of suitable photothermographic film elements, present camera technology has not been applied to photothermographic systems. There is a need to provide image capture capabilities for camera speed photothermographic systems.
The importance of information such as film type, film speed, film exposure information, and information relevant to the processing and subsequent use (e.g. printing or optical scanning) of the film is well understood. Virtually transparent magnetic layers or stripes on film provide a means to record such information. These magnetic layers or stripes provide for the recording of information during film manufacture, reading and/or recording of information during camera use, and reading and/or recording information during subsequent processing or optical scanning. There is a need to read and write magnetic data on thermographic film associated with image capture, thermal processing, and/or optical scanning. Reading and writing information on a magnetic coating or stripe on thermographic film requires solutions to problems different than those encountered in other apparatus. For example, the thermal development conditions may degrade and potentially erase the magnetic information stored on the film. There is therefore a need to read and store the magnetic information so that it can be rewritten onto the film after thermal processing.
The function of a film scanner is to measure optical density at many points on the film being scanned. The density of each pixel, or smallest region of the film being sensed, is measured by illuminating the region with light of a known light intensity and measuring the intensity of the light that is transmitted through the film. Color scans require measuring transmitted light intensity over known spectral bands. Such techniques are disclosed in U.S. Pat. No. 5,684,610--Brandestini et al. The transmitted light intensity can be measured electronically and the electronic record of the transmitted light can be digitized and stored as an electronic file representation of the film image.
The importance and utility of an electronic record of film images is widely known in the art. The electronic file can be easily duplicated and extensively manipulated. Color balance and tone scale can be adjusted. Sharpening and other algorithms to alter image structure can be applied. Annotations and/or graphical elements can be added to the film image data file. The scene can be easily cropped and digitally zoomed. An electronic record of a film image can be easily transmitted and communicated through known electronic communication networks. The electronic record of a film image can also be output to a variety of output devices including ink-jet and thermal wax digital printers. The electronic record can also be manipulated and stored in mass storage devices for rapid retrieval and subsequent processing. There is a need to optically scan thermographic film to provide an electronic file record of the film image information.
Optical writing of sensitometric tables and test patches onto conventional wet processed film to improve imaging system performance is known in the art. Such techniques are disclosed in U.S. Pat. No. 5,667,944--Reem et al. Optical writing of calibrated tablets and patches onto unexposed portions of film is of significant utility. Inspection of processed calibrated tablets or patches allows the processing conditions to be optimized for the remainder of the filmstrip. Furthermore, analysis of the calibrated tablets or patches allows printing and/or scanning algorithms to be refined to achieve an advantaged print or more useful electronic record of the film image data. For example, tone scale and color balance can be corrected and adjusted based on data obtained from calibrated tablets or patches. Optical writing provides a means to store other information on the film such as data associated with processing or scanning conditions. Optical writing also allows information to be written onto exposed regions of the film. For example, a time and date stamp that is readily apparent in a print can be written onto the film at the time of processing. Furthermore, by controlling the optical writing, graphical elements can be added to the original scene prior to processing. There is a need to provide for optical printing onto thermally developable film.